Endometriosis affects 5-10% of reproductive-age women with chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility. Medical treatment with 6 months of danazol or a GnRH agonist and surgical treatment are effective in alleviating symptoms in the short term, but the side effects of medical and surgical intervention preclude indefinite continuation or repeated treatment, and symptoms reoccur in 40-50% of women after treatment cessation. Knowledge of risk or protective factors for recurrence is of great importance, therefore, yet the effect of patient characteristics and behaviors on symptom recurrence likelihood has largely been unexamined. The main objectives of this competing continuation application are to determine the 48-84 month symptom recurrence rate in a cohort of 18-49 year old women with a first-time diagnosis of endometriosis, according to disease severity and treatment, and to assess relationships between symptom recurrence and estrogen-related subject characteristics and behaviors. The study hypothesis is that factors associated with higher estrogen levels, including lack of regular exercise, peripheral body fat distribution, alcohol use, dietary phytoestrogen ingestion, presence of low activity alleles in genes involving estrogen metabolism, and use of hormone replacement therapy, may increase long-term risk of endometriosis symptom recurrence after treatment cessation. The proposed retrospective cohort study will utilize cases (n=337) from the principal investigator's current case-control study of endometriosis risk factors (Reproductive/Contraceptive Risk Factors & Endometriosis, R01 HD33792) conducted within a large health maintenance organization in Washington State. Information available from the cases in that study, including in-person interviews with pre-diagnosis details of medical, reproductive, menstrual, contraceptive, behavioral, and other characteristics; dietary and anthropometric measurements; and values of 4 genetic polymorphisms (GSTM1, COMT, CYP1A1, CYP1A2) will be combined with additional interview information to be collected between 48-84 months after initial diagnosis on treatment details, timing and extent of any recurrence of symptoms, and post-diagnosis estrogen-related characteristics and behaviors. Medical records and pharmacy records will be used as to supplement subject-provided diagnosis, treatment and recurrence information. [unreadable] [unreadable]